Throttle control mechanism



March 22, 1960 A. D. BAKER ET AL THROTTLE CONTROL MECHANISM Filed oct. 21, 1957 A TroRA/Ef United States rrnRorrLn CONTROL MECHANISM Application October 21, 1957, Serial No. 691,334

6 Claims. (Cl. 62215) The present invention relates to an apparatus for controlling the idling speed of an internal combustion engine. It has been found necessary in present day automobiles to provide means for automatically adjusting the idling speed of the engine to compensate for the additional load imposed thereon by certain of the larger accessories such as air conditioning units. Accordingly, the present invention relates to an improved engine idling control system in which the throttle idle setting is automatically adjusted when one of such major accessories is being driven by the engine in order that the engine idling speed may be maintained at a constant value or, if preferred, increased slightly. s

While in general engine idling control devices have been heretoforeutilized for this general purpose, such devices have either been complicated, required the actuation of several control members or were not selectively controllable with the actuation ofa particular accessory.

AIn the present invention means has been uniquely combined with a throttle fast idle cam in such a way as to make the carburetor throttle setting responsive both to engine temperature as well as the actuation of a major `accessory and which arrangement uniquely insures that the engine will be operated at the proper idling speed under all heavy engine accessory load conditions. It is a further object of the present invention to provide an idling speed controlling device which is conjointly operated by a control device adapted to control the operation of a major engine accessory such as an air conditioning unit.

Other details and advantages of the present invention will be apparent from a perusal of the detailed description which follows. Y

In the drawings:

Figure 1 is a view of a carburetor embodying the subject invention;

Figure 1a shows the idle control valve in its on position; and

Figure 2 represents a modified type of idle speed control circuit.

A carburetor is shown generally at 10 and may be of any well known type such as that shown in Patent 2,771,282 Olson et al. Save insofar as the components will be hereinafter described, carburetor 10 does not, per se, constitute a part of the present invention.

Carburetor 10 includes a throttle valve 12 iixedfor rotation upon a shaft 14. A lever 16 is fixed to shaft 14 and is adapted to be suitably articulated through aA rod 18 to the accelerator pedal, not shown, in order that the position of throttle 12 may, in general, be determined by the vehicle operator.

While the operator normally controls the position of the throttle 12, it is necessary when the accelerator pedal isreleased, as during idlingoperation, to provide means whereby the engine will be idled at a speed suicient to prevent stalling. Accordingly, a fast idle adjustmentv screw v20 is provided on a tab 22 on an offset portion A4 oflever' 16. In general when the engine isl atent 2,929,226 .Pete-'ifea Mee. .215@ 12,69

warm and otherwise operating under normal loads, fast idle adjustment screw 20 will have no'control -over the position of the throttle valvev 12.' l

The normal idle adjustment for the throttle 12 will be determined by an adjusting screw 26 which is likewise mounted on lever 16 and is adapted to coa'ct with a fixed stop 28 on the carburetor casing. If the normal idle adjusting screw were set to insure an adquate idling speed under all operating lconditions of the engine, idling speed would be excessive during many conditions. Thus, the fast idle adjustment screw 20 is utilized to supplement the action-of the normal idle Vadjustment screw un'- der certain engine operating conditions as will now beY considered. A

A fast idle cam 30 is pivotally mounted upon a stud 32 fixed to the carburetor casing. t Cam 30 is eccentrically mounted with respect to stud 32 in such a way that it tends to rotate in a counterclockwise directionv about the stud due to the force of gravity acting thereon. Cam 30 includes a progression of low to high step surfaces 34 and which surfaces are disposed adjacent the fast idle adjustment screw 20. A low cam surface is provided at 36 whereas a high cam surface is provided at 38'.

A spring member 40 is suitably ixed to the accelerator control rod 18 biasing the throttle valve lever 16 in a counterclockwise direction thereby urging the fast idleV adjusting screw 20 toward the fast idle cam 30.

A choke valve is indicated generally at 42 and is fixed.l

for rotation with a shaft 44. A lever 46 is also fixed to shaft 44 and has one end of a rod 48 suitably articulatedk thereto. The other end of rod 48 is articulated tothe fast idle cam 30. An automatic choke controlling mechanism is indicated generally at 50 and is ofthe type shown and described in Patent 2,705,484 Jorgensen'. 'Ihe choke controlling mechanism 50 is adapted to oppose the opening of the choke valve with a force which is inversely proportional to engine temperature. As the engine warms the air flow through the carburetor isy is cold, onthe other hand, the choke valve lever 46 will` move the rod 48 upwardly liftingthe fast` idle cam 30 and positioning the high step 38 thereof `adjacent the fast idle adjustment screw 20 preventing the normal closing of the throttle 12 and thereby increasing the idling speed of the engine.-v As the engine temperature warms the fast idle cam 30 will be progressively permitted to move under the influence of gravity in a counterclockwise direction bringing progressively lower step `cam surfaces into engagement with the fast idle adjustment screw and gradually permitting a reduction in the engine idling speed consonant with warmer engine operations.

In addition to providing means for vincreasing the engine idling speed when the engine temperatures are low, it has been found necessary to provide additional means for increasing the throttle idle position to either increase or maintain constant the engine idling speed when accessory loads are imposed on the engine. This has been found to be particularly necessary when a major accessory such as an air conditioning unit indicated generally at 60 is provided. inasmuch as theload imposed by the air conditioning unit 60 is high during idling conditions `relative to the power outputi of theengine, itV is necessary either to adjust the vnormal idle radjustment screw 26 to accommodateY idling operation with the` air conditioning unit 'in operation, supra, or in the alternative apanage to provide means wherebythe .erigine idling speed may be controlled automatically when the unit is` in operation. It is apparent that the latterV alternative is economically and operationally more desirable inasmuch as adjusting the normal idle adjustment screw will cause an excessively high idling engine speed when the air conditioning unit is not in operation as already noted..-

Accordingly, -a unique idle speed ,controlling .mechanism has been' developed and combines with the temperature 4controlled fastV idle system vas well as withthe air conditioning actuating mechanismato provide means for controlling the, engine idling speed in with accessory loads.

A servo mechanism is indicated generally at 62 and includes adiaphragm member 64 peripherally clamped between a pairxof casingmembers 66 and `68. A rod member 70 is-centrally fixedv tok theY diaphragm 64 for movement therewith. The other end of rod 70 is connectedto the fast idle camy 30 througha lost motion slot 72. The-lost. motion connection between' the Lservo device 62 vandthe fast idle cam 39 insures that the engine temperature` control of the cam may ytake place regardless of the servo mechanism except as will be heren inafter described.

Servo 62 includes chamber 74 which is open to the atmosphere and chamber 76 which communicates through a boss 7S with a conduit 80 the latter being in turn connected to a power source, such as the intake manifold, not shown. The control` of servo 62 is achieved througha valve mechanism 82 which -is actually a part of thecair conditioning unit controldevice 84. Device 84 is adapted to be controlled byl the movement f member 86 and among other things 'would' contain suitable switch means for actuating air conditioner 60.

Valve mechanism 82 includes a member 86 slidably disposedin a casing 88 and which may, for instance, be a part of the temperature control lever 90 for the air conditioning unity 60. Casing 88 communicates with conduit 80 intermediate servo 62 and the manifold and with the atmosphere through a port 92. The 'movable valve member 86 includes a longitudinal passage 94 Iformed therein which communicates with a radial passage 96 andV a peripherally relieved portion 98.

When the airconditioning unit is off, as indicated in Figure l, the diaphragm chamber 76 isvented to the atmosphere VWhen the air conditioning unit is operative member 86 is moved to the right by a control lever 90 in which position lthe relieved portion 98 and passages 96 and 94 communicate engine vacuum'with chamber 76 moving the diaphragm upwardly. The upward movements of diaphragm 64 `imparts a similar movement to the control rod 7G causing the fast' idle cam 30 to be moved upwardly until the high step 38 of the cam is adjacent the fast idle adjustment screw 20. in this condition, the degree of idle throttle opening of the throttle -valve 12 will be increased. In this way the idling speed of the engine is increased or maintained at a constant value when the air conditioner has increased the load on the engine.

It is possible to substitute an electrical control system in place of the vacuum control system just described. In this event, a solenoid may be used in place of the servo 62. A diagrammatic representation of an electrical control system which may be utilized with the sub ject invention is shown in Figure 2. In the electrical control system as shown in Figure 2, a refrigeration unit fan is indicated at 100'and is actuated whenever the master switch 102 is closed. The speed of fan iti-tl is determined by the bridge circuit indicated at ldd which includes the multi-throw switch 106. A compressor actuating solenoid is Vshown at 108 and is adapted to be actuated only when a switch 110 is closed along with the master switch 102; A fast idle cam actuating solenoid 112 is' connected in parallel with the compressor solenoid 108 and is likewise energized when the accordance compressor switch is closed. Thus, the added load imposed on the engine by. actuating'the compressor circuit is compensated for by a similar actuation of the fast idle cam 30 to increase the idle opening of the throttle valve 12.

It is apparent that various structural modifications may be made in the aforedescribed engine idle speed controlling device within the scope of the hereinafter appended claims. Y

We claim: v

l. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, an automotive accessory adapted to be driven by the engine, a carburetor for supplying a combustible mixture of fuel and air to said engine, said carburetor having a throttle valve for controlling the quantity of mixture supplied to the engine, a lever mounted for movement with the throttle, said lever including an adjustablefstop member, a gravity actuated fast idle cam eccentrically pivoted on the carburetor and adapted to coact with said stop member to control engine idling speed, temperature responsive means connected to said cam to provide increased throttle opening when the engine is cold and idling, and means operable when said accessory is operative to actuate said cam independently of the temperature responsive means to increase the throttle opening during idling conditions.

2. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising, in cornbination, an automotive'accessory adapted to bedriven by the engine, a carburetor for supplying a combustible mixture of fuel and air to said engine, said carburetor having a throttle' valve for controlling the quantity of mixture supplied to the engine, a lever mounted for movement with the throttle, said lever including an adjustablev stop member, a fast idle cam eccentrically pivoted on the carburetor, said cam including a progression of low to high step surfaces, said'v stop member being adapted to severally engage said plurality of surfaces, said cam adapted to be actuated by gravity to position the low cam step adjacent said stop; temperature responsive means connected to said cam to provide increased throttle opening when the engine is cold and idling, and means operable when said accessoryy is operative to actuate said cam independently of the'temperature responsive means to increase the throttle opening during idling conditions.

3. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising incombination, an automotive accessory adapted to vbe driven by the engine, a carburetor for supplying a combustible mixture of fuel and air to said engine, said carburetor having a throttle valve for controlling the quantity of mixture supplied to the engine, a lever mounted for movement with the throttle, said lever including an adjustable stop member, a fast idle cam eccentrically pivoted on the' carburetor, said cam including a progression of low to high step surfaces, said stop member being adapted to severally engage said plurality of surfaces, said cam adapted to be actuated by gravity to position the low cam step adjacent said stop, temperature responsive means connected to said cam to provide increased throttle opening when the engine is cold andidling, a servo operatively connected to said cam, a conduit adapted to connect said servo with a source of engine vacuum, control means for said accessory, said control means including a valve device in said conduit, said valve device adapted to communicate engine vacuum with the servo to move the cam to increase the degree of throttle opening when the control means actuates the accessory.

4. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, an automotive accessory adapted to be driven by the engine, a carburetor for supplying a combustible mixture of fuel and air to said engine, said carburetor havspaanse ing a throttle valve for controlling the quantity of mixture supplied to the engine, a lever mounted for movement with the throttle, said lever including an adjustable stop member, a gravity actuated fast idle cam eccentrically pivoted on the carburetor and adapted to coact with said stop member to control engine idling speed, temperature responsive means connected to said cam to provide increased throttle opening when the engine is cold and idling, means operable when said accessory is operative to actuate said cam to increase the throttle opening, -and a lost motion connection between said cam and said accessory operable means permitting the temperature responsive means to control the cam independently of accessory operation.

5. Apparatus for controlling the idling speed of the engine of an automotive vehicle comprising in combination, an automotive accessory adapted to be driven by the engine, a carburetor for supplying a combustible mixture of fuel and air to said engine, said carburetor having a throttle valve for controlling the quantity of mixture supplied to the engine, a lever mounted for movement with the throttle, said lever including an adjustable stop member, a fast idle cam eccentrically pivoted on the carburetor, said cam including a progression of low to high step surfaces, said stop member being adapted to severally engage said 'plurality of surfaces, said cam adapted to be actuatedby gravity to position the low cam step adjacent said stop, temperature responsive means connected to said cam to provide increased throttle opening when the engine is cold and idling, means operable when said accessory is operative to actuate said cam to increase the throttle opening, and a lost motion connection between said camvand said accessory operable means permitting the temperature responsive means to control the cam independently of accessory operation.

6. An idling speed controlling apparatus as set forth in claim 3 in which the operative connection between said servo and said cam includes a lost motion device permitting the temperature responsive means to actuate said cam independently of accessory operation.

References Cited in the le of this patent UNITED STATES PATENTS I 2,720,087 Groene Oct. 11, 1955 2,762,235 Olson et al. Sept. 11, 1956 2,807,146 Jackson Sept. 24, 1957 

